Social enterprises, equally as what charities do, contributes to social well-being by combing commerce and charity. Many charities in the UK make changes from charity to social enterprise. Unlike social enterprises making profit for charitable purpose, charities rely on donation from other people. Obviously, merely depending on capital from outside is not effective as making money internally. So why not choose the way that reaches the same goal more effectively?
Picture: Kosri
This makes me think an example I have read about Grameen Bank. Grameen Bank offers micro loan to the poor who have skills to earn more money but are not qualified to loan from normal bank. Unlike charities donating money to people in poverty, Grameen bank provides sustainable way to for the poor to solve survival issue. 
Picture: Grameen Foundation
Grameen bank also makes profit in order to operate the entity but most importantly every dollar the bank earns applies to social well-being. This is what social enterprises do, contributing to philanthropy in an innovative, sustainable and commercial way.